1. Field of the Invention
This invention relates generally to an electrotherapy device. Specifically, this invention relates to a method and apparatus for analyzing a post-shock rhythm of a patient being treated by an electrotherapy device and using the results of the post-shock rhythm analysis to make a decision about patient treatment. Electrotherapy devices include defibrillators, cardioverters and training devices that simulate the operation of an electrotherapy device. Defibrillators include automatic or semi-automatic external defibrillators (AEDs).
2. Description of the Prior Art
Electrotherapy devices are used to provide electric shocks to treat patients for a variety of heart arrhythmias. For example, external defibrillators typically provide relatively high-energy shocks to a patient (as compared to implantable defibrillators), usually through electrodes attached to the patient""s torso. External defibrillators are used to convert ventricular fibrillation (xe2x80x9cVFxe2x80x9d) or shockable ventricular tachycardia (xe2x80x9cVTxe2x80x9d) to a normal sinus rhythm. Similarly, external cardioverters can be used to provide paced shocks to convert atrial fibrillation (xe2x80x9cAFxe2x80x9d) to a more normal heart rhythm.
Sudden cardiac arrest (xe2x80x9cSCAxe2x80x9d) is the leading cause of death in the United States. On average, 1000 people per day die; this translates into one death every two minutes. Most SCA is caused by VF, in which the heart""s muscle fibers contract without coordination, thereby interrupting normal blood flow to the body. The only effective treatment for VF is electrical defibrillation, which applies an electric shock to the patient""s heart. The electric shock clears the heart of the abnormal electrical activity (in a process called xe2x80x9cdefibrillationxe2x80x9d) by depolarizing a critical mass of myocardial cells to allow spontaneous organized myocardial depolarization to resume.
To be effective, the defibrillation shock must be delivered to the patient within minutes of the onset of VF. Studies have shown that defibrillation shocks delivered within one minute after the onset of VF achieve up to a 100% survival rate.
However, the survival rate falls to approximately 30% after only 6 minutes. Beyond 12 minutes, the survival rate approaches zero. Importantly, the more time that passes, the longer the brain is deprived of oxygen and the more likely that brain damage will result. As improved access to defibrillators increases, survival rates from SCA also increase.
AEDs typically use algorithms to determine whether or not a shock should be delivered to a patient. Numerous algorithms and programmable systems are known for recording and analyzing a patient""s cardiac signal. For example, U.S. Pat. No. 5,421,830, to Epstein et al. for xe2x80x9cProgramming System Having Means for Recording and Analyzing a Patient""s Cardiac Signal,xe2x80x9d the specification of which is incorporated, teaches one programming system for detecting an arrhythmia. The programming system is implemented in a manner that enables optimization of the settings of various rhythm detection criteria and/or parameters relating to hemodynamic performance which are programmed into an implanted cardiac stimulating device (xe2x80x9cICDxe2x80x9d). U.S. Pat. No. 5,951,484 to Houim et al. for xe2x80x9cMethod of Non-Invasively Determining a Patient""s Susceptibility to Arrhythmia,xe2x80x9d discloses a method of using biased and unbiased QRS complexes to detect the patient""s susceptibility to an arrhythmia.
The algorithms used by AEDs typically do not rely on patient pulse information, since pulse information is not obtainable through the electrode pads used by the AED and information supplied by the user may or may not be accurate. Failure to use pulse information in determining whether to shock a patient can result in a no-shock decision for a potentially shockable rhythm. This is because AEDs are designed to make shock decisions conservatively. AEDs also analyze electrocardiogram (ECG) data segments received from a patient in isolation from prior analysis results or protocol events.
Notwithstanding the great strides made in developing AED patient analysis systems, improvements are still possible that would improve the efficacy of the treatment and decision making by the AED algorithm assessing patient treatment. What is needed, therefore, is a method of evaluating patient ECG that improves patient treatment.
The present invention includes an electrotherapy device. At least one sensor is operable to sense at least one physiological parameter of a patient. A controller is operably connected to the at least one sensor operable to receive signals from the at least one sensor corresponding to the at least one physiological parameter. Memory is operable to store computer-programming code executed by the controller. The programming code includes decision-making criteria operable to adapt a patient treatment in response changes to the detected at least one physiological parameter. At least one pair of electrodes is operably connected to the controller and operable to administer the treatment to the patient.
The present invention also concerns an electrotherapy device that includes at least one sensor operable to sense at least one physiological parameter of a patient. A circuit is operably connected to the sensor and configured to detect a patient physiological parameter. A controller is operably connected to the circuit and operable to receive signals from the circuit corresponding the to at least one physiological parameter. The controller is configured to implement decision-making criteria responsive to changes in the measured parameter values, and operative to adapt patient treatment based upon the decision-making criteria.
Additionally, the present invention relates to a method for performing electrotherapy. The method includes detecting at least one physiological parameter of a patient. The at least one physiological parameter is analyzed. A patient treatment is adapted in response to changes in the detected at least one physiological parameter. The treatment is administered to the patient.
Furthermore, the present invention provides a method for performing electrotherapy on a patient. The method includes an operator of an electrotherapy device administering to a patient based upon instructions produced by the electrotherapy device and adapting the instructions produced by the electrotherapy device based upon detected changes in at least one physiological parameter of the patient in response to prior treatment administered to the patient with the electrotherapy device.
An electrotherapy device is disclosed. The electrotherapy device includes a sensor, a controller coupled to the sensor and configurable to detect cardiac signals, and memory having computer programming code stored in the memory. The computer programming code is executed in the controller and has decision-making criteria that, in response to previously detected cardiac signals, may adapt patient treatment. The computer programming code may further include decision-making criteria. The decision-making criteria can operate to adapt patient treatment by generating a shock/no-shock decision or it may adapt patient treatment by generating a therapy decision. A user interface may be provided that is coupled with the controller. The user interface would enable a user to adapt the decision-making criteria of the computer-programming algorithm. The user interface could include, for example, a tactile input device associated with the device. The decision-making criteria are optimized to utilize patient physiological parameters in making its decision. Patient physiological parameters include, for example, heart rate, conduction variable and stability variable, to name a few. Typically, the device will analyze cardiac signal such as, ECG parameters, heart rate, conduction variable and stability variable. The computer programming code is typically executed in the controller to recommend alternative patient therapies based on prior patient events and/or arrhythmia analysis algorithm decisions.
An electrotherapy device may also include a sensor and a circuit coupled to the sensor. The circuit is configured to detect a patient physiological parameter. The device may also include a controller coupled with the circuit, configured to implement decision-making criteria responsive to the measured parameter values and operative to adapt patient treatment based upon the decision-making criteria. Patient physiological parameters typically include ECG parameters, heart rate parameters, heart conduction variables, and heart stability variables, blood pressure, SPO2, and any other suitable physiological parameters. The decision-making criteria utilize patient physiological parameters, including prior decision making results, to determine the appropriate therapy to administer. From this information, the decision-making criteria generate a shock/no shock decision, or generate a therapy decision (for instance, a decision to administer appropriate pharmaceutical agents).
A method for performing electrotherapy can include providing a circuit and a sensor operable to detect a patient physiological parameter, and control circuitry. The control circuitry can implement decision-making criteria operable to adapt treatment based upon the decision-making criteria and detect the patient physiological parameter. The control circuitry can also analyze the patient physiological parameter and determine whether a prior patient physiological parameter has been analyzed. If a prior patient physiological parameter has been analyzed the prior patient physiological parameter is analyzed in conjunction with the analyzed patient physiological parameter. A treatment decision is made based on the evaluation. If a prior patient physiological parameter has not been analyzed, the analyzed patient physiological parameter is analyzed and a treatment decision is made based on the evaluation. The circuitry can also cause treatment to be delivered to the patient. As described above, patient physiological parameter include, for example, ECG segment comprises analyzing at least one of heart rate, heart condition and heart stability, blood pressure, and SPO2, to name a few. Causing therapy to be delivered may also include enabling shock delivery to a patient with the adapted control circuitry based upon known prior analysis results. The sensor may be a patient electrode and the circuit may be a cardiac event detection system.
Still other objects and advantages of the present invention will become readily apparent by those skilled in the art from a review of the following detailed description. The detailed description shows and describes preferred embodiments of the present invention, simply by way of illustration of the best mode contemplated of carrying out the present invention. As will be realized, the present invention is capable of other and different embodiments and its several details are capable of modifications in various obvious respects, without departing from the invention. Accordingly, the drawings and description are illustrative in nature and not restrictive.